Described herein are an assembly of, an apparatus for and a method of assembly of a tube and a part located at least partially within the tube. Release of residual stresses so the memory of the manufacturing process used to make the part and the tube permits expansion thereof for engagement therebetween that is not found in the literature or practiced in the field. The literature is of interest for its teachings of the knowledge of skilled artisans at the time of this invention of an assembly of, apparatus for and method of assembly of a tube and a part located at least partially therewithin. The assembly of microscopic sized tubes and parts presents additional difficulties.
Typically tubes are stoppered, plugged or sealed by application of a press fit, shrink fit or wedging component into the bore thereof. Chemicals such as adhesives, sealants or glues are frequently applied to make a fluid tight joint. The accurate application of chemicals to make a small joint fluid tight presents added difficulties of placement and clean up. Often the chemicals used can interfere with the operation of the assembly being made therewith.
Optical fibers or fiber optic chemical sensor used in vivo as probes must be sensitive to slight changes in gas or ion concentrations. Chemicals can also leach into the blood stream. For example, U.S. Pat. No. 4,200,110 has a fiber optic probe with an ion permeable membrane enclosure about the distal ends of a pair of fiber optics. Change in color of a pH sensitive dye is detected. The addition of sealants and the like is something to be avoided.
U.S. Pat. No. Re 31,879 has a method for measuring concentration of an analyte in a sample that changes color and/or the intensity of light emitted from a fluorescent indicator attached to the fiber. U.S. Pat. No. 5,047,208 has an optical sensor for blood gas measurement with a pH sensitive absorption dye between the end of the fiber and the mirror. The mirror is located by a tube which carries a mirror spaced from and coaxially aligned with the fiber so the dye can be in the space. These and other patents are typical of the microscopic constructions required for in vivo blood analysis and the manner in which structures have been made.
U.S. Pat. No. 5,005,576 has an optical sensor for blood gas measurement capable of measuring pH and pCO.sub.2 with light absorption dyes between the end of the fiber and the mirror. The mirror is located in the distal end of the sheath with a silicone glue to close off the end of the probe.
U.S Pat. No. 5,047,627 has an optical sensor for blood gas measurement capable of measuring pH, pO.sub.2 and pCO.sub.2 with light absorption or fluorescent dyes between the ends of the fibers and the mirrors. The mirrors attached to the dye pellet for each fiber with glue and seal the fiber end. Certainty and consistency of assembly is not always repeatable with adhesive attachment and chemicals in the adherent may adversely influence the chemistry of the sensor and therefor measurement accuracy.
U.S. Pat. No. 4,889,407 has an optical fiber with arrayed cells to substantially cover the cross sectional area of the fiber. An indicator sensitive to an analyte in a medium is used to determine pH and pCO2 in vivo in blood. That commonly assigned patent is incorporated herein by reference since the disclosure herein may be applicable to that fiber distal end.